I disagree with Mohit. I don't think a session facade is defined as a components which wraps entity beans. Facades are unified interfaces to a complex system or sub-system. That system may include, but is not limited to, entity beans.

The difference between session facades and message facades is the same as the difference between session beans and message beans. When you want a synchronous invocation and return value use a session facade. When you want an asynchronous invocation and can live with a possible delay in the processing of the request, use a message facade. Just pick up any EJB book and read about where to use MDBs and where to use SBs. I don't see how the fact that these MDBs and SBs provide a unified interface to a complex sub-system should make a difference.

"Message facade comes over few of the drawback of session facade.Using session facade,the problems related to performance,coupling and maintainability can be resolved.But problems it is bit time consuming b.coz of synchronization.Session bean takes one request from one client.Clent will block whole process untill the whole process is completed.This problem is resolved by message driven beans.Using message driven beans by adding the capability to execute use cases in asynchronous,fault tolerant manner.
Seesion beans run in synchronized manner and MDB run in asynchronise manner.This difference will make it clear the differnce between Session facade and Message facade.Is it clear,If it doen't help plese revert back. "

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